Abstract

System delays affect user performance and experience when
interacting with computers. We investigated the effects of different prediction
relations between delay duration and response requirements on user performance.
In one experiment, delay duration predicted, to different degrees (50 % vs. 75 %
vs. 100 %), the following system response. Predictability substantially increased
users’ response speed, while adaptation was highly flexible, between
different prediction regimes. In a second experiment, users’ responses
predicted system delay duration. Compared to the first experiment, users’
response speed was moderately increased, while the adaptation was rather
inflexible across different prediction regimes. In a third experiment, we
directly compared both types of predictability. The results confirmed a stronger
and more flexible adaptation effect when time predicted the system response,
compared to when users’ responses predicted time. These findings have
important implications for scheduling data transmission rates across different
users in internet-based parallel computing.